Prutitis - aka itchiness

Allergy Problems in Dogs: "Pruritis is the name for itchiness that causes pets to scratch. Several chemical reactions occur in the skin that stimulate the nerves, causing the brain to feel the itch. We treat a scratching pet by attempting to eliminate these reactions at the source and controlling the body's response to them as well.
Some of the chemicals involved in itching are prostglandins, arachodonic acid (a specialized fatty acid) and leukotreines. By using treatments that inhibit the action of these factors at the skin level, such as antihistamines and fatty acid competitors, we can sometimes control the itching without using corticosteroids such as prednisone. If we work to control other irritating factors such as fleas, dry skin and secondary bacterial infections we can also further reduce itching. Each of these steps is very important because pets have an 'itch threshold'. This is the point where all of the sources of itching finally add up to enough irritation to cause the irresistible urge to scratch. Just like pain thresholds, these levels vary from pet to pet. Control of every factor that possible is important to your dog's health and comfort. Pruritis is a complication of many diseases. Only by careful examination, diagnostic tests and sometimes even trial and error can we come to understand what causes the itching in a particular pet and how we can best control it. "

--chemical reactions in the skin
E.S.